So my entire dieting life... I have lost weight slowly and had trouble keeping it off. I would get to like 174 and have some candy at a Christmas party and gain like 10 lbs... instantly. And then, I couldn't lose it. Until.. 2009. My doctor did a Vitamin D3 blood test and it turned out I was severely deficient. 15 ng per ml. I was supposed to be over 30 (at that time) and now the levels have been raised to higher (suggested 30 to 60). I got my blood level up to 45 or so. I should have known... I still could gain weight but I did notice it seemed harder to do.

So come January this year I went on a diet, when my blood level was 45 ng. I lost weight fast... (of course there was more to it than just vitamin D but this is the first time I actually lost like *normies* at the age of 42 I lost better than 18). This is the first diet I was ever on with normal Vitamin D. I made my goal for the first time ever. Then come August I started eating normally again. Did I gain hand over foot? No. No I didn't. In fact, I have gained no more than 3 lbs since going off the diet 3 months ago.

If there was one thing I would say to any dieter it is that you need to pay attention to Vitamin D3

- it has to be blood level. Vitamin D is fat soluble. So you can take 4000 IU and 3000 will be trapped in your fat. There is no way to know... unless you get your blood level tested.
- it has to be vitamin d3. d2 is a plant based level and it doesn't work as well.
- Vitamin D 3 is a HORMONE. It was named vitamin incorrectly.
- Vitamin d 3 has been shown to reduce insulin resistance.
- Vitamin d 3 has been shown to be an Angiogenesis inhibitor. I bet you have heard of Angiogenesis with regard to cancer. It is how cancer cells get blood to thrive. But turns out fat cells grow exactly the same way. So Vitamin D has been shown to inhibit this process in FAT cells and also cancer.
- Many studies have now shown that it does have an effect on weight loss.
- Studies have shown that Vitamin D3 increases muscle mass.
- Vitamin D3 is hard to get from food. Very few foods have it. It is also hard to get from the sun. The oft heard 15 minutes in the sun doesn't work in certain areas of the US and in highly polluted places. You must supplement.

Since Vitamin D3 has been implicated in cancer prevention -- why not do it?

If you don't believe me... google any of these facts and check them out yourselves.

I tested on the low end of normal for vitamin D and my doctor prescribed me vitamin D2, she told me that she believes it is better to take d2 than d3. My levels came up and I never had any symptoms. It is a good thing to check when you have your physical.

My doctor also found me with reduced vitamin D levels. I do take D3, not D2, even my vegan parents take D3 because doctors say the D2 is not as easily absorb-able as the D3 version.

I do think anyone that has the health insurance to do so, to get it tested and chances are, it will be low. Mine was super low despite living in a place with sun and not wearing sunscreen. It's not enough to sit for 15 minutes, especially if your levels are really low. I had to take mega-doses until my D levels came up to minimum. Now, I just supplement with over-the-counter supplements to maintain it.

My doctor also found me with reduced vitamin D levels. I do take D3, not D2, even my vegan parents take D3 because doctors say the D2 is not as easily absorb-able as the D3 version.

I do think anyone that has the health insurance to do so, to get it tested and chances are, it will be low. Mine was super low despite living in a place with sun and not wearing sunscreen. It's not enough to sit for 15 minutes, especially if your levels are really low. I had to take mega-doses until my D levels came up to minimum. Now, I just supplement with over-the-counter supplements to maintain it.

I tried to look into the differences between D3 & D2. It appears some of the early studies on D3 indicated it has been better but studies have flip flopped. Some studies show D2 better, others show D3 but the differences are minimal. All I know is I only take D2 and my levels are good.

Well I suppose it only matters if your levels are good. But I am going to guess that your doctor prefers D2 because that is what is typically what the pharmaceutical companies provide and of course, the doctor feels more comfortable with that.

The reason I warned is because some people take D2 and assume they will be getting their blood levels up but that is not always the case because generally, it is thought to require more to produce the same blood levels as D3 -- and that has been my experience. So someone could pop a 50000 IU D2 pill and be like -- oh of course this will get my levels up.. and then, find out they didn't really move.

Thank you AnnRue for this post! I searched internet about Vitamin D3 and found lots of interesting info about it. Vitamin D3 seems to be frowned upon in EU. Big drug companies are trying to forbid the D vitamin sale. That says something.

I agree on Vit D3. My doc has me take 5000IU a day. I have hypothyroidism and hashimotos and Vit D deficiency is tied to both conditions, as well as all other autoimmune disorders. I live in Alaska, so it's nearly impossible for me to get adequate vitamin D from sunlight exposure. Strike that- it IS impossible, except for the short summer months.

Wow I had no idea! I live in a sunny place and just always assumed my levels were fine, I will definitely have to check with my doctor on this during my next level! Thanks for bring it to my attention everyone!!!

I can't believe more people don't know about this... it makes me so angry that people are suffering (as I did) this way. If there is one thing you do this year to lose weight please please please do this.

Yes vitamin D! And obese women tend to have lower levels of it (correlation - not necessary causation - however, there is some evidence that lack of vitamin D can cause weight gain - also some evidence that being an obese women can make it hard to absorb the right amounts). So get tested - and take a supplement! And in fact, ther is a lot of literature that suggests the amount that lab tests say is "normal" isn't even enough - so everyoen should consider this important supplement.